Performance of asbestos fibre counting laboratories by transmission electron microscopy

In France, the owners of buildings have been obliged since February 1996 to ascertain whether asbestos has been incorporated into surfacing materials, insulation products or false ceilings. In certain circumstances, there is also a requirement to measure the airborne asbestos fibre concentration, Th ree years (1996-1998) of asbestos fibre count reporting are evaluated for t he proficiency testing scheme organized in France to evaluate the performan ce of laboratories using an indirect-transfer transmission electron microsc opy procedure to measure the airborne asbestos fibre concentration. Each ye ar eight filters are distributed to each participating laboratory. These fi lters are obtained by filtering a suspension containing chrysotile or amphi bole fibres. In 1996, 36% of the laboratories were rated 1 (the best perfor mers; i.e. those providing counts close to the reference value), Performanc e improved appreciably in the Last round where 85% of the laboratories were rated i, (C) 2001 British Occupational Hygiene Society. Published by Elsev ier Science Ltd. All rights reserved.